Bolt with deformable washer



Feb. 1l, 1969 l R, ESTES ETAL 3,426,819

BOLT WITH DEFORMABLE WASHER original Filed sept. 4, 1964 @QAM l f` Q32i? f4 V United States Patent C) 3,426,819 BOLT WITH DEFORMABLE WASHERRonald Estes, Garden City, and Harold A. Storch, Birmingham, Mich.,assignors to Federal Screw Works, Detroit, Mich., a corporation ofMichigan Continuation of application Ser. No. 394,443, Sept. 4, 1964.This application Feb. 20, 1967, Ser. No. 617,421 U.S. Cl. 151-69 2Claims Int. Cl. F16b 43/ 00, 29/00 ABSTRACT OF THE DISCLOSURE A fastenerassembly including a bolt having a head, a thread shank, and anon-circular locking portion intermediate the head and the thread. Adeformable washer which is U-shaped in cross-section is deformed intononrotatable locking engagement with the non-circular portion upontightening down of a-counterbored nut member.

This application is a continuation of application Ser. No. 394,443,filed Sept. 4, 1964, which is now abandoned.

This invention relates to fastener assemblies and particularly to afastener assembly including a male threaded member, a lock nut, and adeformable washer adapted to be nonrotatably locked on the male threadedmember upon the tightening of the nut.

It is an object of the present invention to provide a fastener assemblyof the above character consisting of a male threaded member, a nut, anda washer in which the washer is deformed by application of the nut andis thereby permanently secured on the male threaded memlber Iso that thewasher will serve to hold the fastened parts in assembly even if the nutcomes oif the male threaded member.

It is another object of the present invention to provide a fastenerassembly of the above character in which the washer is held againstrotation on the male threaded member and serves to insulate the nut fromrotational forces produced by angular movement of one of the fastenedparts.

It is still another object of the present invention to provide afastener assembly of the above character in which the washer isautomatically held in a centered position on the male threaded memberduring its deformation and will be so located on the male threadedmember as to apply equal forces to the nut which is seated against it.

It is still another object of the present invention to provide afastener assembly of the above character which lends itself to use witha self-locking nut and in which the washer assists in holding the nutagainst rotation.

It is still another object of the present invention to provide afastener assembly which is reliable in use, inexpensive to manufacture,and well suited for its intended purpose. These and other objects of thepresent invention will become apparent from the following detaileddescription taken in conjunction with the accompanying drawings,wherein:

FIG. l is a sectional view taken through the bolt axis of a fastenerassembly embodying the principles of the present invention, the assemblybeing shown partially applied to a pair of members to be fastened; and

FIG. 2 is a view of the fastener assembly of FIG. 1 showing the assemblycompletely installed; and

FIG. 3 is a sectional view of the structure illustrated in FIG. 2 takenalong the line 2 2 thereof; and

FIG. 4 is a sectional view of the structure shown in FIG. 1 with thebolt being rotated 30 from the position thereof s'hown in FIG. 1.

Referring now to the drawings, FIG. 1 shows a pair of members 20 and 22to be held together, the members 20 and 22 being illustrated asgenerally at sheets of material held in face to face abuttingrelationship and provided with aligned bolt-receiving apertures. A malethreaded member in the form of a bolt 48 is illustrated as projectingthrough the members 20` and 22 and a nut 26a is shown threaded onto thebolt 48. A washer 60 is positioned on the bolt 48 between the nut 26aand the member 22. A head 50 of the bolt will be seen to engage themember 20 to permit tightening of the nut 26a against the washer 60. Thebolt 48 is formed with a cylindrical shank portion 52 disposed withinthe members 20 and 22, a reduced diameter portion 54 of noncircularcross sectional shape and threads 56. The specic cross sectional shapeof the bolt portion 54 is hexagonal and it will be seen to have axiallyextending edges 54a formed between flat .surfaces 54b. As is best shownin FIG. 4, the edges 54a are disposed on a diameter equal to the crestdiameter of the bolt threads 56.

The hexagonal bolt portion 54 is designed to receive the washer 60 whichis made from sheet metal and is provided with two parallel walls 62which are of annular shape and which are spaced apart in a directionaxially of the bolt. The walls 62 are interconnected at their innerdiameters by a bight portion 64 of U-shaped cross section, which definesan aperture y65 located centrally in the washer 60. The aperture 65initially possesses a' diameter slightly greater than or equal to thecrest diameter of the threaded extremity 56 of the bolt. By this meansthe washer may be fitted onto the bolt by being slid over the threads 56and onto the hexagonal portion 54. In this position the washer will becentered by the edges 54a so that it is disposed with its centersubstantially coincident with the axis of the bolt. The nut 26a can thenbe applied to the bolt. As the nut 26a is threaded down on the boltthreads 56, its inner face engages the outermost wall -62 and moves ittoward the innermost wall closing the space between the two walls 62.When this happens, the bight portion 64 is deformed radially inwardlyand the edges 54a dig into the bight portion deforming the aperture 65from a circular to a noncircular shape. Thus, the edges 54a and theadjacent portions of the walls 54 prevent the washer 60 from rotating onthe bolt. The portions of the aperture 65 which lie between the edges54a will be located radially inwardly of the diameter on which the crestof the threads 56 are located. By this means the washer is providedwi-th a portion which will engage the threads 56 to prevent the washerfrom coming orf the bolt in the event of loss of the nut 26a from theassembly.k

The nut 26a is provided with a counterbore 27 on the side adjacent themember 22 into which the hexagonal portion 54 may extend when theassembly is completely installed (FIGURE 2). This counterbore 27 clearsthe hexagonal portion 54 but nevertheless provides the necessary bearingengagement with -the washer 60.

It will be appreciated that the various parts of the assembliesillustrated herein are adapted to be made from steel, but may also bemade from other suitable materials. Furthermore, the bolt is designed tobe made 'by the use of production cold forming equipment. Thus, thefastener assembly of the present invention may be manufactured at arelatively low cost, yet it will provide a highly reliable fastening,having marked safety features which lend it to use in criticalapplications.

The nut 26a, illustrated herein, is preferably of the prevailing torquetype of locknut. Various locknuts of this type are well known in theindustry .and one, for example, is shown in Stover U.S. Patent No.2,464,729. According to to a locknut of this type, the nut `26a isdeformed at its end opposite from the counterbore 27 to provide aradially inwardly deformed thread portion operable to engage the boltthreads and prevent accidental or inadvertent rotation of the nut on thebolt. It will be noted that the was'her is initially positioned on thebolt prior to is deformation in a centered condition. In other words,the aperture of the Washer is centered with respect to the bolt axisprior to deforming contact with the nut. By this means, it is assuredthat the nut Will deform the Washer equally on all sides to set up equalstresses Within the washer and prevent any eccentric loading of t'henut.

What is claimed is:

1. A fastener assembly including a male threaded member having threadsat one end thereof and a portion of noncircular hexagonal cross sectionlocated axially inwardly of said threads, said portion of noncircularhexagonel cross section having a minimum diameter less than the crestdiameter of said threads and a plurality of relatively sharp edges lyingon an imaginary cylinder located at the maximum diameter thereof, thespaces between said edges occupying a greater portion of said cylinderthan said edges, a nut adapted to be threaded on said threads and awasher having an aperture and a deformable portion surrounding saidaperture, said aperture being of a size and shape enabling said washerto be advanced freely past said threads onto said non-circular hexgonalcross-section portion, said deformable portion being deformable into thespaces between said edges upon the tighening of said nut thereagainst toreduce said aperture to a diameter less than the crest diameter of saidthreads and to cause said edges to dig into said deformable portionwhereby said washer is prevented from rotating on and coming off of saidreduced diameter portion.

2. A fastener assembly including a male threaded member having threadsat one end thereof and a portion of noncircular cross section locatedaxially inwardly of said threads, said portion of noncircular crosssection having a minimum diameter less than the crest diameter of saidthreads and a plurality of relatively sharp edges lying on an imaginarycylinder located at the maximum diameter thereof, the spaces betweensaid edges occupying a greater portion of said cylinder than said edges,a nut adapted to be threaded on said threads and a Washer having anaperture and a deformable portion surrounding said aperture, saidaperture being of a size and shape enabling said Washer to be advancedfreely past said threads onto said reduced diameter portion, saiddeformable portion being deformable into the spaces between said edgesupon the tightening of said nut thereagainst to reduce said aperture toa diameter less than the crest diameter of said threads and to causesaid edges to dig into said deformable portion whereby said washer isprevented from rotating on and coming off of said reduced diameterportion, said washer having a pair of parallel flat annular wallsinterconnected by an annular portion of U- shaped cross section locatedat the inner periphery thereof and defining said aperture.

References Cited UNITED STATES PATENTS 293,295 2/1884 Agnew 151-2858,191 6/1907 Logan 151-3 '924,467 6/ 1909 Humphrey 151-3 2,470,927 5/1949 Hale `151--69 2,605,121 7/1952 Ensinger 151-68 2,955,885 10/1960Storch 151-3 3,118,718 1/1964 Babey 151-69 FOREIGN PATENTS 774,5745/1957 Great Britain.

MARION PARSONS, JR., Primary Examiner.

U.S. Cl. X.R.

